There’s only one reason Manny Pacquiao should not retire immediately after this fight. That is to take on Floyd Mayweather early next year. That fight falls through, he should hang up his spurs, or gloves, and ride into the sunset or fade into the pages of legend.

I’m assuming of course that Pacquiao will have won the fight Saturday night in Las Vegas or Sunday morning in Manila. (I’m writing this at the site of the fight on the eve of the fight, courtesy of my friend, William Tsieng, Solar big boss.) To go by what I’ve been reading these past few weeks, that seems a done deal. Pacquiao has appeared sharp, demolishing sparring partners with a fury he hasn’t shown in some time. More to the point, he appears motivated, a thing he has shown even less of in some time, which explains his rediscovered form.

A Yahoo story appeared some months ago that revealed his mindset. That was the first time Pacquiao and Marquez announced their fourth bout to the public, and Pacquiao was furiously scribbling a memo to himself, “I have to knock him out! I have to knock him out!” For good reason. He hasn’t really won against Juan Manuel Marquez convincingly. Nothing short of a knockout will persuade his public and himself to believe he’s the superior boxer. Nothing short of a knockout will persuade the world, if not his countrymen, to believe he’s one of the best pound-for-pound boxers to have walked this earth or stepped on to the ring.

Not the least of the reasons for it is that the expectations from him have shot sky-high. That was so particularly last year after he had a couple of years that saw him at the peak of his powers. Indeed, that we saw quite graphically in the fate and faces of his opponents—Oscar de la Hoya, Ricky Hatton, Miguel Cotto, Antonio Margarito—who ended up in the hospital after having their features violently rearranged. And with Pacquiao confidently, or arrogantly, depending on whether you’re friend or foe, arranging to do a concert after his fight with Cotto.

I saw the last one live courtesy of William as well, and I personally thought it was a draw. Marquez threw more punches that landed, but Pacquiao threw the heavier ones that rocked Marquez. And Marquez pretty much just danced away the whole night, stopping now and then to throw punches. Pacquiao may have won that fight on the basis of the score cards, he lost it on the basis of expectations. Everyone expected him to have come a long way from the days when he could just hold Marquez at bay. Everyone expected him to send Marquez to the same place he did De la Hoya and company earlier. To the canvas, to the hospital, to obscurity.

Of course if the unimaginable happens, if Pacquiao loses to Marquez since the guy is motivated too—Marquez figures he won the last bout—indeed if the more unthinkable happens, if Marquez instead does to Pacquiao what Pacquiao vows to do to him, then game over.

The decision will have been made for Pacquiao.

Like the entire nation of course, my mind refuses to admit that possibility. Like all Filipinos, my heart expects him to recapture more than an echo of his glory days. Enough to catapult him to the final reel, to his final battle, to his final reckoning with Mordor, or Mayweather.

But that remains epically iffy to this day, notwithstanding Pacquiao agreeing to a smaller share of the purse, notwithstanding noises from the Mayweather camp about the fight finally pushing through early next year. But that doesn’t happen, Pacquiao should stop fighting the Timothy Bradleys of this world, the losers of this world, who can only tarnish his luster. And compromise his afterlife, or life after boxing.

He should call it a day. He should call it a career. He should call it a blessing.

But that’s the hardest thing to do, quit while you’re ahead. That’s the hardest thing to see, knowing when to quit. That’s the one thing athletes and other fierce competitors share with spouses—they’re the last to know. The lure of “just one more” is hard to resist, which has laid low the best of them, which has brought down the mightiest of them. It’s not just the money, it’s not just the cajoling and fawning of hangers-on, it’s also the gladiatorial ecstasy, it’s also the roar of the crowd. Just one more. It’s a gamble of course, but in Pacquiao’s case, well, gambling happens to be his second favorite sport.

Even Muhammad Ali could not escape its clutches. He fought his greatest fight not against Sonny Liston, not against George Foreman, not against Joe Frazier, but against the US government, and won. But he went on to fight the one foe no one has beaten before, and no one will beat ever: Time.

He lost.

He should have quit after the Thrilla in Manila, which was the acme of his boxing career, the climax of his boxing life. Just as Michael Jordan should have quit after Utah. Instead Ali fought on, for the most part against patsies like Chuck Wepner, which succeeded only in giving Sylvester Stallone the inspiration to write “Rocky.” Jordan at least merely ended up with an embarrassing third coming, Ali ended up with a body quivering violently from a disease called Parkinson’s, which many suspect he got from getting one punch too many.

It won’t be the easiest thing for Pacquiao to do if he wins this fight, and wins it big. But he’ll win a bigger fight for his profession, for his career, and for himself if at the end of it he contemplates the end of things. (Indeed he should contemplate quitting politics as well, a fight he can never hope to be a champion in. But that’s another story.) I can only hope that what happened yesterday (by the time this comes out) has given him the luxury of a choice.

The other scenario, which is that he lost it, and lost it big, can only be the stuff of bangungot.

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